Revert "nir: Drop the unused instr arg for src/dest copy functions."

This reverts commit c3a01841184ee8303c0c5ebe58491301622c5ad6.

Acked-by: Alyssa Rosenzweig <alyssa@collabora.com>
Reviewed-by: Jason Ekstrand <jason.ekstrand@collabora.com>
Reviewed-by: Emma Anholt <emma@anholt.net>
Part-of: <https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/12910>

src/compiler/nir/nir_search.c

@@ -526,7 +526,8 @@ construct_value(nir_builder *build,
       assert(state->variables_seen & (1 << var->variable));
 
       nir_alu_src val = { NIR_SRC_INIT };
-      nir_alu_src_copy(&val, &state->variables[var->variable]);
+      nir_alu_src_copy(&val, &state->variables[var->variable],
+                       (void *)build->shader);
       assert(!var->is_constant);
 
       for (unsigned i = 0; i < NIR_MAX_VEC_COMPONENTS; i++)